JP4247255B2 - Access point, wireless LAN system, and wireless control method - Google Patents

Description

  The present invention relates to a wireless LAN access point, a wireless LAN system including the access point, and a wireless control method in the access point.

  In a wireless LAN (Local Area Network), an access point communicates its presence and information such as a network identifier (for example, ESS-ID (Extended Service Set Identifier)) and DTIM (Delivery Traffic Indication Message) information to a wireless communication terminal. A beacon signal for notification is transmitted (for example, see Patent Document 1 below). In a wireless LAN in a call system in which voice data is transmitted and received between terminals, a beacon signal includes bitmap information that is information indicating which radio communication terminal has voice data. As a result, a plurality of wireless communication terminals can simultaneously perform voice data communication.

Audio data is sequentially transmitted from the access point to the wireless communication terminal designated as the audio data destination by the bitmap information. That is, the downlink data transmitted from the access point to the wireless communication terminal is not transmitted to a plurality of wireless communication terminals at the same time, and after the data transmission to the first wireless communication terminal is completed, the second data is transmitted. The data transmission to the other wireless communication terminal is started, and the transmission is started after the voice data transmission of the other wireless communication terminals is completed to the wireless communication terminals that are transmitted after the third unit.
JP 2003-60657 A

  However, the above background art has the following problems. The beacon signal is normally transmitted at a constant cycle. Further, the generation interval of audio data in a wireless communication terminal is usually longer than the transmission interval of beacon signals. In such a situation, when a plurality of wireless communication terminals are connected to one access point and communication is performed, transmission of downlink data is biased after transmission of a specific beacon signal from the access point. There is a possibility that. In that case, there is a high possibility that the downlink data transmitted from the access point and the uplink voice data transmitted from the wireless communication terminal collide. When a data collision occurs, a delay or the like occurs in data transmission / reception in the wireless communication terminal.

  The present invention has been made to solve the above-described problems, and an access point and a wireless LAN system that can efficiently use a wireless band by preventing the occurrence of data collision in the wireless LAN. It is another object of the present invention to provide a radio control method.

  In order to achieve the above object, an access point according to the present invention is a wireless LAN access point, and a terminal that detects the number of wireless communication terminals that establish a connection in the wireless LAN via the access point A number detection unit, a generation interval information acquisition unit for acquiring information indicating a generation interval in the wireless communication terminal of data transmitted from the wireless communication terminal, the number of wireless communication terminals detected by the terminal number detection unit, and the generation One beacon based on information indicating the generation interval acquired by the interval information acquisition unit and information indicating a preset transmission interval of a beacon signal transmitted from the access point to the wireless communication terminal Setting means for setting a maximum number of pieces of information specifying a wireless communication terminal that is included in a signal and is a destination of data to be transmitted. And wherein the Rukoto.

  In the access point according to the present invention, the maximum number of information specifying the wireless communication terminal that is the destination of data included in the beacon signal is set. The maximum number is set based on the number of wireless communication terminals that have established a wireless LAN connection via an access point, the generation interval of data transmitted from the wireless communication terminal, and the access point communicating wirelessly. This is performed based on a preset transmission interval of a beacon signal transmitted to the terminal. Therefore, the number of downlink data transmitted from the access point to the wireless communication terminal during the beacon signal transmission interval is not biased with respect to the number of the wireless communication terminals and the data generation interval in the wireless communication terminal. It will be a thing. As a result, according to the access point of the present invention, it is possible to prevent the occurrence of data collision in the wireless LAN and efficiently use the wireless band.

Preferably, the setting means sets the maximum number by multiplying the number of wireless communication terminals by a numerical value indicating the transmission interval and dividing the result by a numerical value indicating the generation interval to an integer value . According to this structure, this invention can be implemented reliably.

  The access point has a control means for controlling so that information specifying the wireless communication terminal that is the destination of the data is included in a plurality of beacon signals when the data to be transmitted to the wireless communication terminal exceeds the maximum number. It is desirable to provide further. According to this configuration, since the information of the wireless communication terminal that is the destination of all data to be transmitted is included in the beacon signal, data transmission can be performed reliably.

  The number-of-terminals detecting means detects an increase / decrease in the number of the wireless communication terminals from a connection request or a disconnection request transmitted from the wireless communication terminal, and establishes a connection via the access point based on the increase / decrease. It is desirable to detect the number of wireless communication terminals. According to this configuration, the access point can reliably detect the number of wireless communication terminals that have established a wireless LAN connection via the access point, so that the present invention can be reliably implemented. it can.

  In order to achieve the above object, a wireless LAN system according to the present invention is a wireless LAN system including an access point and a wireless communication terminal, and the access point is connected to the wireless LAN via the access point. A terminal number detecting means for detecting the number of wireless communication terminals that have established a connection; a generation interval information acquiring means for acquiring information indicating a generation interval in the wireless communication terminal of data transmitted from the wireless communication terminal; The number of the wireless communication terminals detected by the number detection unit, the information indicating the generation interval acquired by the generation interval information acquisition unit, and the beacon signal transmitted from the access point to the wireless communication terminal are set in advance. Based on the information indicating the transmission interval, the wireless communication that is the destination of the transmitted data included in one beacon signal. Characterized in that it comprises a setting means for setting a maximum number of information for identifying the terminal, the.

  Also in the wireless LAN system according to the present invention, the number of downlink data transmitted from the access point to the wireless communication terminal during the beacon signal transmission interval is equal to the number of the wireless communication terminals and the generation of data in the wireless communication terminal. There is no bias with respect to the interval. Thus, according to the wireless LAN system of the present invention, it is possible to prevent the occurrence of data collision in the wireless LAN and efficiently use the wireless band.

  By the way, the present invention can be described as an invention of an access point as described above, and can also be described as an invention of a communication control method as follows. This is substantially the same invention only in different categories, and has the same operations and effects.

  That is, the communication control method according to the present invention is a wireless control method at a wireless LAN access point, and detects the number of wireless communication terminals that establish a connection in the wireless LAN via the access point. A step, a generation interval information acquisition step for acquiring information indicating a generation interval of the data transmitted from the wireless communication terminal, and a number of wireless communication terminals detected in the terminal number detection step, and generation interval information acquisition The transmission included in one beacon signal based on the information indicating the generation interval acquired in the step and the information indicating the preset transmission interval of the beacon signal transmitted from the access point to the wireless communication terminal A setting step for setting a maximum number of information for specifying the wireless communication terminal that is a destination of the data to be transmitted; Characterized in that it comprises.

  In the present invention, the number of downlink data transmitted from the access point to the wireless communication terminal during the beacon signal transmission interval is biased with respect to the number of the wireless communication terminals and the data generation interval in the wireless communication terminal. There will be no. Thus, according to the present invention, it is possible to prevent the occurrence of data collision in the wireless LAN and to efficiently use the wireless band.

  Hereinafter, various preferred embodiments of an access point, a wireless LAN system, and a communication control method according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a configuration of an access point 10 according to the present embodiment, and a wireless LAN system 1 including the access point 10. The wireless LAN system 1 includes an access point 10 and a plurality of wireless communication terminals 20. The access point 10 and the wireless communication terminal 20 can perform wireless communication with each other, and the wireless communication terminal 20 constitutes a wireless LAN 30 by the access point 10. The access point 10 is also connected to a wired network, and is connected to a call server 40 that provides a call function for the wireless communication terminal 20 via the wired network. The wireless communication terminal 20 can be connected to the call server 40 via the access point 10.

  The access point 10 performs wireless communication with the wireless communication terminal 20 as described above, performs wired communication with the call server 40, and transmits information to and from these devices 20 and 40 as necessary. Send and receive. The access point 10 periodically transmits a beacon signal that notifies the wireless communication terminal 20 of its existence and information such as a network identifier and DTIM information. The beacon signal includes the above-described bitmap information, that is, information specifying the wireless communication terminal 20 that is the destination of the audio data to be transmitted. The detailed configuration of the access point 10 will be described later.

  The wireless communication terminal 20 is used by a user and has a function of configuring the wireless LAN 30 by performing wireless communication with the access point 10. By receiving the beacon signal transmitted from the access point 10, the wireless communication terminal 20 can detect the presence of the access point 10 and perform wireless communication with the access point 10.

  In addition, the wireless communication terminal 20 can perform a call by transmitting and receiving voice data to and from another terminal in response to provision of a call function by the call server 20. The wireless communication terminal 20 can transmit / receive voice data to / from the other terminal by transmitting a call request, which is a connection request for performing a call to / from another terminal, to the call server 40. As such, a connection (call session) is established with the call server 40. Voice data related to a call is transmitted / received to / from a communication partner terminal via the call server 40. In addition, when audio data is transmitted to the wireless communication terminal 20, since the bitmap information is included in the beacon signal, the wireless communication terminal 20 has audio data to be transmitted to itself. Can be recognized.

  The radio communication terminal 20 generates audio data transmitted for a call with another terminal, and the audio data is generated at a predetermined generation interval (hereinafter referred to as a payload interval). The payload interval is set in advance in the call server 40 and is notified from the call server 40 to the wireless communication terminal 20 when the connection is established. The payload interval is usually 20 ms to 100 ms. When the call is terminated, a disconnection request is transmitted from the wireless communication terminal 20 to the call server 40, and the call server 40 performs a disconnection process, whereby the connection is disconnected and the call ends.

  Specifically, the wireless communication terminal 20 is configured by hardware such as a CPU (Central Processing Unit), a memory, and a communication module, and the above functions are realized by the operation of these components.

  The call server 40 provides a call function for the wireless communication terminal 20 as described above. Specifically, a VoIP (Voice over Internet Protocol) communication is used as the call function, and a VoIP communication server is used as the call server 40. When the call server 40 receives a call request and a disconnection request from the wireless communication terminal 20, the call server 40 receives a call request and a request so that the access point 10 can grasp the number of wireless communication terminals 20 that have established a connection. Notify that the disconnect request has been received. Specifically, the call server 40 is configured by hardware such as a CPU, a memory, and a communication module, and the above functions are realized by the operation of these components.

  Subsequently, the access point 10 will be described in detail. As shown in FIG. 1, the access point 10 includes a wireless communication unit 11, a wired communication unit 12, a beacon signal control unit 13, a terminal number detection unit 14, a generation interval information acquisition unit 15, and a setting unit 16. It is configured with.

  The wireless communication unit 11 is a wireless communication unit that transmits and receives data by wireless communication with the wireless communication terminal 20. The transmitted / received data includes voice data related to a call. Data transmitted to the wireless communication terminal 20 includes data input from the wired communication unit 12 and data received from another wireless communication terminal 20 by the wireless communication unit 11. Data received from the wireless communication terminal 20 is output to the wired communication unit 12 according to the data, or transmitted to another wireless communication terminal 20. The wireless communication unit 11 also transmits (broadcasts) the beacon signal generated by the beacon signal control unit 13.

  The wired communication unit 12 is a wired communication unit that performs wired communication with the call server 40. Specifically, data exchanged between the wireless communication terminal 20 and the call server 40 is relayed. When the wired communication unit 12 receives voice data for the wireless communication terminal 20 from the call server 40, the wired communication unit 12 temporarily buffers the voice data. The wired communication unit 12 sequentially transmits the audio data to the wireless communication terminal 20 after the beacon signal including the bitmap information related to the wireless communication terminal 20 that is the destination of the audio data is transmitted.

  The beacon signal control unit 13 is means for generating and controlling a beacon signal. The beacon signal is output to the wireless communication unit 11 at a predetermined transmission interval (hereinafter referred to as a beacon interval), and transmitted from the wireless communication unit 11 to the wireless communication terminal 20. The beacon interval is set in advance, and specifically, an interval of about 20 ms to 100 ms. Also, the beacon interval is usually one half of the payload interval.

  Further, when the beacon signal control unit 13 receives voice data to be transmitted from the call server 40 to the wireless communication terminal 20 by the wired communication unit 12, the beacon signal includes the bitmap information related to the wireless communication terminal 20 in the beacon signal. Specifically, for example, a Mac address or an IP (Internet Protocol) address is used as the bitmap information. In the beacon signal control unit 13, the maximum number of bitmap information included in one beacon signal is set by the setting unit 16. When the data to be transmitted to the wireless communication terminal 20 exceeds the above maximum number, that is, when the number of bitmap information exceeds the set maximum number, the bitmap information is converted into a plurality of beacon signals. Include separately. Specifically, for example, bitmap information is sequentially included in the beacon signal, and when the maximum number is exceeded, it is included in the next beacon signal. That is, the beacon signal control unit 13 is a control unit that controls to include the bitmap information divided into a plurality of beacon signals when the audio data to be transmitted to the wireless communication terminal 20 exceeds the maximum number.

  The number-of-terminals detection unit 14 is a number-of-terminals detection unit that detects the number of wireless communication terminals 20 that have established a connection with the wireless LAN 30 via the access point 10. Specifically, the detection of the number is performed as follows. The terminal number detection unit 14 holds information on the number of wireless communication terminals 20 that are currently connected via the access point 10. The number-of-terminals detecting unit 14 receives the notification that the call request and the disconnection request have been received from the wireless communication terminal 20 from the call server 40, and the number of the wireless communication terminals 20 that have established a connection via the access point 10. The number of wireless communication terminals 20 is detected on the basis of the increase and decrease and the information on the number of wireless communication terminals 20 held. Information on the number of detected wireless communication terminals 20 is notified to the setting unit 16.

  In addition, according to said method, although the detection of the number of the radio | wireless communication terminals 20 which established the connection via the access point 10 can be performed reliably, the detection of the number of the said radio | wireless communication terminals 20 It may be performed by a method. For example, a method of counting the number of connections established through the access point 20 may be used.

  The generation interval information acquisition unit 15 is a generation interval information acquisition unit that acquires information indicating the payload interval in the wireless communication terminal 20. Specifically, the generation interval information acquisition unit 15 is included in a control signal transmitted from the call server 40 to the radio communication terminal 20 when a connection is established between the radio communication terminal 20 and the call server 40. The information is acquired with reference to the information. The acquired information is notified to the setting unit 16.

  The setting unit 16 is a setting unit that sets the maximum number of bitmap information included in one beacon signal transmitted from the access point 10 to the beacon signal control unit 13. The setting of the maximum number is information indicating the number of wireless communication terminals 20 that have established a connection via the access point 10 detected by the terminal number detection unit 14, the payload interval acquired by the generation interval information acquisition unit 15, And based on information indicating the beacon interval. Here, the information indicating the beacon interval is acquired by making an inquiry to the beacon signal control unit 13.

  As the maximum number, the number is calculated by multiplying the number of wireless communication terminals 20 that have established a connection via the access point 10 by the numerical value indicating the beacon interval and dividing by the numerical value indicating the payload interval. Is done. Specifically, for example, assuming that the number of wireless communication terminals 20 established through the access point 10 is 5, the beacon signal transmission interval is 20 ms, and the payload interval is 40 ms, an integer value of 5 × 20/40 The maximum value is calculated as “3”. Such a maximum number is set such that the number of downlink data transmitted from the access point 10 to the wireless communication terminal 20 during the beacon interval is the number of wireless communication terminals 20 with which connection is established via the access point 10. And the payload interval in the wireless communication terminal 20 are not biased. The maximum number setting uses the number of wireless communication terminals 20 that have established connections via the access point 10, even if data is transmitted to all of these wireless communication terminals 20, excessive bias is caused. This is to eliminate it.

  If the maximum number is set using the rules as described above, the present invention can be reliably implemented. However, it is not always necessary to use the above-mentioned criteria, and depending on the situation, the number of wireless communication terminals 20 that have established a connection through the access point 10, information indicating the beacon interval, and information indicating the payload interval are included. The appropriate maximum number of setting methods used can be determined.

  If the payload interval is longer than the beacon interval, the maximum number is not set. This is because there is no bias with respect to the payload interval in the number of downlink data transmitted from the access point 10 to the wireless communication terminal 20 during the beacon signal transmission interval. The functional configuration of the access point 10 has been described above.

  FIG. 2 shows a hardware configuration of the access point 10. FIG. 2 shows a hardware configuration of the access point 10. As shown in FIG. 2, the access point 10 includes a CPU 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 103, a storage device 104 such as a hard disk, a wireless communication module 105 for performing wireless communication, and an antenna 106. , And hardware such as a wired communication module 107 for performing wired communication. By operating these components, each function of the access point 10 described above is exhibited.

  Subsequently, processing (communication control method) executed in the wireless LAN system 1 including the access point 10 according to the present embodiment will be described using the flowchart of FIG. 3 and the sequence diagrams of FIGS. 4 and 5. First, processing in the access point 10 will be described using the flowchart of FIG. 3, and then processing of the entire wireless LAN system 1 including the wireless communication terminal 20 and the call server 40 using the sequence diagrams of FIGS. Will be described. This process is a process when a plurality of wireless communication terminals 20 perform voice communication using the function of the call server 40.

  In the access point 10, first, information indicating the payload interval is acquired by the generation interval information acquisition unit 15 (S01, generation interval information acquisition step). This is based on information transmitted from the call server 40 to the radio communication terminal 20 when a call request is transmitted from the radio communication terminal 20 to the call server 40 via the access point 10 and a call session is established. Done. Information indicating the acquired payload interval is notified to the setting unit 16. If the information indicating the payload interval has been acquired before and stored in the generation interval information acquisition unit 15, it need not be repeated.

  Subsequently, the number-of-terminals detection unit 14 detects the number of call sessions through the access point 10, that is, the number of wireless communication terminals 20 that have established a connection through the access point 10 (S02, terminal number detection step). ). Specifically, when the call server 40 receives a call request and a disconnection request from the wireless communication terminal 20 as described above, it is detected by receiving a notification to that effect. Information indicating the number of detected wireless communication terminals 20 is notified to the setting unit 16.

  Subsequently, the setting unit 16 determines whether or not there are a plurality of call sessions (S03). If it is determined that there are not a plurality of call sessions, there is no significance in setting the maximum number of bitmap signals included in the beacon signal, so that the process is not performed (the process proceeds to S06 described later). When it is determined that there are a plurality of call sessions, the setting unit 16 acquires information indicating the beacon interval from the beacon signal control unit 13. The setting unit 16 determines whether the payload interval is longer than the beacon interval (S04). If it is determined that the payload interval is not longer than the beacon interval, it is not meaningful to set the maximum number for the bitmap signal included in the beacon signal as described above, so that the processing is not performed (S06 described later). Move on to processing).

  When it is determined that the payload interval is longer than the beacon interval, the setting unit 16 calculates the maximum number of bitmap signals included in the beacon signal and sets it in the beacon signal control unit 13 (S05, setting). Step). When the maximum number is set in the beacon signal control unit 13, when voice data of the maximum number or more is transmitted from the call server 40 to the wireless communication terminal 20 in one beacon interval, the bitmap information is a beacon signal. The control which is divided and included is performed. This control is continuously performed while the maximum number is set.

  Thereafter, when a call request and a disconnection request are transmitted from the wireless communication terminal 20 to the call server 40 and the number of call sessions increases or decreases (S06), the access point 10 passes through the access point 10 by the terminal number detection unit 14. The number of call sessions is detected (S02), and the same processing as described above is repeated.

  Next, processing of the entire wireless LAN system 1 including the wireless communication terminal 20 and the call server 40 will be described using the sequence diagrams of FIGS. 4 and 5. First, processing when the number of call sessions increases will be described. This process is a process when the four radio communication terminals 20B to 20E establish a call session with the call server 40 via the access point 10. In this process, the payload interval is 40 ms and the beacon interval is 20 ms.

  First, a call request is made from the radio communication terminal 20A to the call server 40 to start a call (S11). At this time, in the access point 10, the call request is relayed by the wireless communication unit 11 and the wired communication unit 12. The call server 40 receives the call request and controls to establish a call session (S12). In this control, information indicating the payload interval in the radio communication terminal 20A is included in the control signal and transmitted to the call server 40 radio communication terminal 20A. In the radio communication terminal 20A, audio data is generated according to this payload interval while a call is being made.

  In the access point 10, a control signal including information indicating the payload interval is relayed by the wireless communication unit 11 and the wired communication unit 12, and the control information is referred to by the generation interval information acquisition unit 15 to acquire the payload interval. (S13, generation interval information acquisition step). Information indicating the acquired payload interval is notified to the setting unit 16. Note that the information indicating the payload interval need not be repeated because it does not need to be repeated if it has been performed before that time.

  On the other hand, the call server 40 notifies the access point 10 that the call request has been received from the wireless communication terminal 20. In the access point 10, the terminal number detection unit 14 receives the notification via the wired communication unit 12. Based on this notification, the number-of-terminals detection unit 14 detects the number of call sessions through the access point 10, that is, the number of wireless communication terminals 20 that have established a connection through the access point 10 (S14, terminal). Number detection step). Information indicating the number of detected wireless communication terminals 20 is notified to the setting unit 16.

  Since there are a plurality of call sessions (five) and the payload interval is longer than the beacon interval, the access point 10 calculates the maximum number of bitmap signals included in the beacon signal by the setting unit 16, and the beacon signal control unit 13 (S15, setting step). Here, since the number of wireless communication terminals 20 that have established a connection via the access point 10 is 5, the transmission interval of beacon signals is 20 ms, and the payload interval is 40 ms, the integer value is set to 5 × 20/40. The value is incremented and the maximum number is set to “3”.

  Here, voice data for the five wireless communication terminals 20 </ b> A to 20 </ b> E is transmitted from the call server 40 to the access point 10. In the access point 10, the voice data is received by the wired communication unit 12 (S16). These audio data are temporarily buffered in the access point 10 (wired communication unit 12 thereof).

  Subsequently, when the beacon interval time has elapsed since the previous beacon transmission, at the access point 10, the beacon signal control unit 13 generates a beacon signal. Here, although the bitmap signal is included, but the maximum number is set to “3”, the beacon signal includes the bitmap signals related to the three wireless communication terminals 20A to 20C (S17, control step). . In the conventional access point, bitmap signals relating to all (five) wireless communication terminals 20A to 20E are included. The generated beacon signal is output from the beacon signal control unit 13 to the wireless communication unit 11 and transmitted from the wireless communication unit 11 to the wireless communication terminals 20A to 20C (S18). Note that since the beacon signal is broadcast, the beacon signal is also received by the wireless communication terminals 20D and 20E (the same applies to the following description).

  Subsequently, the buffered audio data is sequentially transmitted from the wireless communication unit 11 to the wireless communication terminals 20A to 20C (S19 to S21). The transmitted voice data is received by the wireless communication terminals 20A to 20C.

  Subsequently, when the beacon interval time has elapsed since the previous beacon transmission, at the access point 10, the beacon signal control unit 13 generates a beacon signal. The beacon signal includes the bitmap signals related to the remaining two wireless communication terminals 20D and 20E (S22, control step). The generated beacon signal is output from the beacon signal control unit 13 to the wireless communication unit 11 and transmitted from the wireless communication unit 11 to the wireless communication terminals 20D and 20E (S23).

  Subsequently, the buffered audio data is sequentially transmitted from the wireless communication unit 11 to the wireless communication terminals 20D and 20E (S24, S25). The transmitted voice data is received by the radio communication terminals 20D and 20E. The above is the processing when the number of call sessions increases.

  Next, processing when the number of call sessions decreases following the above processing will be described using the sequence diagram of FIG. First, the wireless communication terminal 20E issues a disconnection request to the call server 40 in order to end the call (S31). At this time, in the access point 10, the wireless communication unit 11 and the wired communication unit 12 relay the disconnection request. The call server 40 receives the disconnect request and performs a process for disconnecting the call session (S32).

  Subsequently, the call server 40 notifies the access point 10 that a disconnect request has been received from the wireless communication terminal 20. In the access point 10, the terminal number detection unit 14 receives the notification via the wired communication unit 12. Based on this notification, the number-of-terminals detection unit 14 detects the number of call sessions via the access point 10, that is, the number of wireless communication terminals 20 that have established a connection via the access point 10 (S33, terminal). Number detection step). Information indicating the number of detected wireless communication terminals 20 is notified to the setting unit 16.

  Since there are a plurality of call sessions (four) and the payload interval is longer than the beacon interval, the access point 10 calculates the maximum number of bitmap signals to be included in the beacon signal by the setting unit 16 and performs beacon signal control. Is set in the unit 13 (S34, setting step). Here, since the number of wireless communication terminals 20 that have established a connection via the access point 10 is 4, the transmission interval of beacon signals is 20 ms, and the payload interval is 40 ms, the maximum number is 4 × 20/40 and “ 2 "is set.

  Here, voice data to the four wireless communication terminals 20 </ b> A to 20 </ b> D is transmitted from the call server 40 to the access point 10. In the access point 10, the audio data is received by the wired communication unit 12 (S35). These audio data are temporarily buffered in the access point 10 (wired communication unit 12 thereof).

  Subsequently, when the beacon interval time has elapsed since the previous beacon transmission, at the access point 10, the beacon signal control unit 13 generates a beacon signal. Here, since the bitmap signal is included, but the maximum number is set to “2”, the beacon signal includes the bitmap signals related to the three wireless communication terminals 20A and 20B (S36, control step). . The bitmap signal related to the wireless communication terminal 20C that was included in the same beacon signal as the bitmap signal related to the wireless communication terminals 20A and 20B is included in the next beacon signal. The generated beacon signal is output from the beacon signal control unit 13 to the wireless communication unit 11 and transmitted from the wireless communication unit 11 to the wireless communication terminals 20A and 20B (S37).

  Subsequently, the buffered audio data is sequentially transmitted from the wireless communication unit 11 to the wireless communication terminals 20A and 20B (S38, S39). The transmitted voice data is received by the radio communication terminals 20A and 20B.

  Subsequently, when the beacon interval time has elapsed since the previous beacon transmission, at the access point 10, the beacon signal control unit 13 generates a beacon signal. The beacon signal includes the bitmap signals related to the remaining two wireless communication terminals 20C and 20D (S40, control step). The generated beacon signal is output from the beacon signal control unit 13 to the wireless communication unit 11 and transmitted from the wireless communication unit 11 to the wireless communication terminals 20C and 20D (S41).

  Subsequently, the buffered audio data is sequentially transmitted from the wireless communication unit 11 to the wireless communication terminals 20C and 20D (S42, S43). The transmitted voice data is received by the wireless communication terminals 20C and 20D. The above is the processing when the number of call sessions decreases.

  As described above, according to the present embodiment, by setting the maximum number of bitmap information included in a beacon signal, it is possible to prevent excessive bitmap information from being included in one beacon signal. . That is, the number of downlink data transmitted from the access point 10 to the wireless communication terminal 20 during the beacon signal transmission interval is equal to the number of the wireless communication terminals 20 and the data generation interval in the wireless communication terminal 20. And there will be no bias. Thereby, according to the present embodiment, it is possible to prevent the occurrence of collision between downlink data and uplink data in the wireless LAN and to efficiently use the radio band.

  When a data collision occurs, a data transmission delay occurs as a result. However, in this embodiment, data is not forcibly transmitted at a timing when the radio space is crowded, and as a result, data transmission is made faster. Can do. This also allows more wireless communication terminals 20 to communicate as compared to the conventional wireless LAN system.

  Also, as in this embodiment, when the data to be transmitted to the wireless communication terminal 20 exceeds the maximum number, if the bitmap information is included in a plurality of beacon signals, all the data to be transmitted Since the bitmap information related to the data is included in the beacon signal, the data can be reliably transmitted.

  In the present embodiment, the data generated and transmitted / received in the wireless communication terminal 20 is voice data. However, the data is not necessarily limited to voice data. Data is generated at regular intervals and a beacon signal is transmitted by the wireless LAN. The present invention can be applied in the case of transmission / reception triggered by.

It is a figure which shows the structure of the wireless LAN system comprised including the access point which concerns on embodiment of this invention, and the said access point. It is a figure which shows the hardware constitutions of the access point which concerns on embodiment of this invention. It is a flowchart which shows the process (communication control method) performed by the access point which concerns on embodiment of this invention. It is a flowchart which shows the process (communication control method) performed with the wireless LAN system which concerns on embodiment of this invention. It is a flowchart which shows another example of the process (communication control method) performed with the wireless LAN system which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wireless LAN system, 10 ... Access point, 11 ... Wireless communication part, 12 ... Wired communication part, 13 ... Beacon signal control part, 14 ... Terminal number detection part, 15 ... Generation interval information acquisition part, 16 ... Setting part, DESCRIPTION OF SYMBOLS 101 ... CPU, 102 ... RAM, 103 ... ROM, 104 ... Storage device, 105 ... Wireless communication module, 106 ... Antenna, 107 ... Wired communication module, 20 ... Wireless communication terminal, 30 ... Wireless LAN, 40 ... Call server.

Claims (6)

A wireless LAN access point,
Terminal number detection means for detecting the number of wireless communication terminals that have established a connection in the wireless LAN via the access point;
Generation interval information acquisition means for acquiring information indicating a generation interval of the data transmitted from the wireless communication terminal in the wireless communication terminal;
The number of the wireless communication terminals detected by the terminal number detection unit, the information indicating the generation interval acquired by the generation interval information acquisition unit, and a beacon signal transmitted from the access point to the wireless communication terminal Setting means for setting a maximum number of pieces of information specifying the wireless communication terminal that is a destination of data to be transmitted, included in one beacon signal, based on information indicating a preset transmission interval;
Access point with The setting means sets the maximum number by multiplying the number of the wireless communication terminals by a numerical value indicating the transmission interval and dividing the result by a numerical value indicating the generation interval to an integer value. The access point according to Item 1.
  When the data to be transmitted to the wireless communication terminal exceeds the maximum number, control means is further provided for controlling the information specifying the wireless communication terminal that is the destination of the data to be included in a plurality of beacon signals. The access point according to claim 1 or 2.   The terminal number detecting means detects an increase / decrease in the number of the wireless communication terminals from a connection request or a disconnection request transmitted from the wireless communication terminal, and establishes a connection via the access point based on the increase / decrease. The access point according to claim 1, wherein the number of wireless communication terminals that are present is detected. A wireless LAN system including an access point and a wireless communication terminal,
The access point is
A terminal number detecting means for detecting the number of the wireless communication terminals that have established a wireless LAN connection via the access point;
Generation interval information acquisition means for acquiring information indicating a generation interval of the data transmitted from the wireless communication terminal in the wireless communication terminal;
The number of the wireless communication terminals detected by the terminal number detection unit, the information indicating the generation interval acquired by the generation interval information acquisition unit, and a beacon signal transmitted from the access point to the wireless communication terminal Setting means for setting a maximum number of pieces of information specifying the wireless communication terminal that is a destination of data to be transmitted, included in one beacon signal, based on information indicating a preset transmission interval;
A wireless LAN system comprising: A wireless control method in a wireless LAN access point,
A terminal number detection step of detecting the number of wireless communication terminals establishing connection in the wireless LAN via the access point;
A generation interval information acquisition step of acquiring information indicating a generation interval in the wireless communication terminal of data transmitted from the wireless communication terminal;
Number of the wireless communication terminals detected in the terminal number detection step, information indicating the generation interval acquired in the generation interval information acquisition step, and a beacon signal transmitted from the access point to the wireless communication terminal A setting step for setting a maximum number of pieces of information specifying the wireless communication terminal that is a destination of transmitted data included in one beacon signal, based on information indicating a preset transmission interval;
A wireless control method comprising:

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